This study proposes to address key issues in the definition, assessment, and treatment of negative symptoms in schizophrenia. We shall systematically compare the construct validity of three current scales for the assessment of negative symptoms; examine the empirical overlap among negative symptoms, depression, and neurological disorder; assess the convergent validity of different scales intended to measure blunted affect or anhedonia; and determine the effectiveness of a dopamine precursor in the treatment of negative symptoms. A series of 60 patients with a consensus diagnosis of schizophrenia (according to Research Diagnostic Criteria) will be assessed at three time points: end of placebo, end of 5 weeks of neuroleptic treatment, and end of 5 weeks neuroleptic plus either L-Dopa or placebo. Assessments will include standard structured psychiatric interview, ratings of negative symptoms, behavioral observation, neurological examination and CT scans, intelligence testing, and biochemical measures associated with depression or schizophrenia (e.g. DST, MAO). The comparison of the relationship between various scales of negative symptoms, depression, neurological soft signs, and the measures above will allow us: (1) to assess the extent to which separate constructs exist, (2) to assess the nature of the relationship between positive and negative symptoms, (3) to test the hyposthesis that negative symptoms are mediated by dopaminergic underactivity, and (4) to assess our ability to treat negative symptoms. The long-term implications of this study, therefore, bear directly on the etiology and treatment of negative symptoms in schizophrenia.